To your health: Healthseeker, a Facebook game that launched this summer, encourages users to take on healthy “missions.” When players complete the actions, they are rewarded with points, virtual gifts, and approval from friends in their social network.

Can your social network make you healthier? It’s a question that health organizations are asking more and more as a wave of new gaming experiments aim to persuade players to think and act differently while having fun.

In June, Vancouver game consulting company Ayogo launched a Facebook game called HealthSeeker that awards “life experience” points or virtual gifts when players with diabetes make small lifestyle changes. For example, it might assign a challenge such as not putting sugar in a single cup of coffee and then reward the player for completing the mission.

The challenge of this kind of game isn’t to convince people of something but to get them to act. “People are already emotionally committed to their health,” says Michael Fergusson, the founder and CEO of Ayogo. “They know they need to eat better and exercise.” But approaching that challenge all at once can seem overwhelming and thankless. “We pay them to take healthy actions,” says Fergusson. Reinforcing those small actions could turn them into habits that add up to better health.

“The game is an ongoing exploration for each player,” adds Manny Hernandez, cofounder and president of the Diabetes Hand Foundation, a nonprofit social-media group that worked with Ayogo and the Joslin Diabetes Center to develop the game. “We hope that through that it can become a very strong source of support for the player,” he says. So far, more than 3,000 people have signed up.

Businesses see value in the concept. “We were really trying to utilize the game players’ own online social network as a source of inspiration and support,” says Susan Holz, a public-affairs and communications representative at the German pharmaceutical company Boehringer Ingelheim, which funded the project as part of an initiative to encourage creative online games related to diabetes.

The real power of the game lies in the principle of reciprocity, the tendency to do something positive for someone who did something positive for you. Game designers take advantage of reciprocity by making it easy for users to send gifts to friends (“You just accepted this pig” in FarmVille, or “Thank Don by sending a free mystery bag back!” in Mafia Wars). Even if users know that the cost of a gift is minimal–often no more than a mouse click–“in general we found people will value the thing they receive,” says Fergusson.

In HealthSeeker, a user can send a “Kudo”–a virtual gift designed to be interesting or amusing–to reward friends for completing a task such as going a day without chocolate. When they receive a Kudo, users feel rewarded and acknowledged for doing something difficult, Fergusson explains. They will also feel a subtle but powerful obligation to return the favor, he says: “That obligation drives the loop of social games.”

The game also draws on the power of social networks in other ways. Users can accept challenges from friends, which Fergusson says makes them more likely to take on the recommended mission (the average player is working on two active missions; players who have accepted a friend’s challenge average four). What’s more, users tend to return to the game more frequently when their friends are also playing.

While it’s too early for HealthSeeker to have gathered more than anecdotal evidence of the game’s success, other games have shown conclusively that they can alter behavior–even more than expected at times. MovieSet is a website that chronicles movie production to generate advance buzz for largely unknown films before promos hit TV or radio. When it launched a behind-the-scenes Web show last year, it initially attracted few viewers. The prerelease excitement that MovieSet craved wasn’t there.